Humidity responsive device



April 9, 1935. F' s MARCELLUS 1,997,468

HUMIDITY RESPONSIVE DEVICE Filed March 31, 1952 lhedhick S.Mar\oe||us,

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Patented Apr. 9, 1935 UNITED STATES PATENT GFFICE HUMIDITY RESPONSIVE DEVICE l Fredrick S. Marcellus, Scotia, N. Y., assignor to General Electric Company, a corporation of New York Application March 31, 1932, Serial No. 602,183

3 Claims. (Cl. 297-1) My invention relates to humidity responsive deportion of the sack to the tube by means of suitvices andhasfor its principal object the provision able binding material I3. A liquid I4 lls the of a simple, easily used device for indicating or sack I2 and partially fills the tube II. controlling humidity, which may be readily pro- In order to make the device responsive to varia- 5 duced at small cost and which is durable and tions in humidityasleeve I5is slipped around the 5 does not require careful handling. Other and fursack I2. The sleeve I5 may be composed of any ther objects and advantages will become apparent suitable material which is expansible and conas the description proceeds. tractible with variations in moisture content. Al-

In accordance with my invention in its preferred though I am not restricted to any particular maform, I provide a tube having the opening in one terial I find satisfactory results may be obtained 10 end closed by attaching thereto a sack of flexible by utilizing ahollow cylinder of wood, for example, material-which is relatively unaffected by variapine, with the grain running substantially in the tions in humidity. A quantity of liquid fills the direction of the axis of the sleeve or cylinder I5. sack and partially fills the tube. The sack is In case wood or a similar material is used for the closely surrounded by abody composed of amatesleeve I5, a decrease in relative humidity will 15 rial having the property of expanding and concause a drying out of the material and a consetracting with variations in moisture content. quent contraction, decreasing the internal as well Consequently, as the relative humidity of the suras the external diameter of the sleeve. This in rounding atmosphere changes, the moisture contime will compress the sack I2 and drive the liquid tent of this ,surrounding body changes and the I4 toahigher levelinthe tube II. Likewise when 20 flexible tube is compressed or released, thereby the relative humidity rises the diameter of the forcing a greater or less amount of liquid into sleeve I5 will increase, permitting the sack I2 to the tube. Suitable means responsive to the quanexpand and the level of the liquid I4 to fall in the tity of liquid in the tube are provided. For tube I I. Although I prefer to utilize a cylindriexample, in connection with a transparent tube, Cal Sleeve l5 and an elOIlgeted Seek l2 in Order 25 a scale may be provided calibrated in any suitable to increase the amOuDt 0f liquid displaced by a units such as per cent relative humidity or if the given relative variation in dimension of the sleeve device is desired to transmit indications to a disl5; it Will be understood that I am nOt limited t0 tance or to control other apparatus in response the exact proportions or shapes of the parts illusto variations in humidity, I may employ a contrated in the drawing. 30 ducting fluid and provide contacts at various If desired a plug I9 of cotton or any other points within the tube so that electrical circuits suitable material may be employed to prevent may be closed or opened in response to variations spillage of the liquid I4 when the device is moved in the quantity of liquid contained in the tube. or handled. Preferably the plug I9 is so con- The arrangement is a modification of that disstructed that air may pass through and the in- 35 closed in my copending application, Serial No. ner portion of the tube may remain at atmos- 602,182, led March 31, 1932, and such features pheric pressure. Y as come within the scope of said application are The arrangement here illustrated has the adclaimed therein. However, the features of my invantage that a relatively secure' and lasting union 40 vention falling Within the scope of the present between the sack or bulb I2 and the tube II may 40 application and which I believe to be novel and be obtained easily at small cost. It will be appatentable will be pointed out in the claims apparent that inmrny arrangement, since the mapended hereto. My invention itself, however, terial from which the sleeve I5 is produced need may be more clearly understood by referring to notbe impervious to the liquid I4, the accuracy the following description taken in connectionwth and reliability of my device would not be im- 45 the accompanying drawing. paired by minor imperfections in the sleeve I5 Referring now more in detail to the drawing, such as cracks or weak spots which would neces- I provide a tube I I composed of any suitable subsitate the rejection of the sleeve I5 if it were instance such as glass and a sack I2 composed of tended to hold the liquid I4. For this reason the any suitable flexible material substantially unsleeve I5 may be produced more easily, quickly,

affected by variations in humidity such as soft and cheaply than would otherwise be the case. rubber. The sack I2 is attached to the lower end Indications of relative humidity may be obof the tube II, preferably by means of cement or tained by reading the height of the liquid I4 in other suitable adhesive, and if desired, the permatube II by means of a scale I6. The apparatus nency 0f the union iS assured by binding the upper may also be utilized to control electrical circuits 55 in response ito variations in humidity by providing electrical contacts I1 and I8 at any desired points in the tube H. In this case the liquid I4 ,comprises a conducting liquid,I preferably one eration of `my invention, together with the ap- YV,paratus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrativeA and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters 'Patent of the United States, is,-

1. A humidity responsive device comprising a tube, an elongated sack attached to one end of said tube, closing the opening therein and composed of a iiexible material relatively unaiected by variations in humidity, a liquid filling said `sack and partially lling said tube, a body surrounding said sack and composed of a material which expands and contracts with variations in moisture content therebyrvariably compressing said sack and causing the amount of liquid contained in said tube to vary with variations in humidity.

2. A humidity responsive device comprising a tube, a sack attached to one end of said tube and closing the opening therein and composed of a exible material relatively unaffected by variations in humidity, a liquid iilling said sack and partially lling said tube, a body surrounding said sack and composed of a fibrous material expansible and contractible with variations in moisture content thereby variably compressing said sack and causing the amount of liquid in said tube to vary with variations in humidity.

3. A humidity responsive device comprising a tube, an elongated sack attached to one end of said tube and closing the opening therein and composed of a flexible material relatively unaffected by variations in humidity, a liquid filling said sack and partially filling said tube, a hollow wooden body having a substantially cylindrical bore, said sack occupying said bore, thereby being variably compressed by the contraction and expansion of said wooden body and causing the amount of liquid in said tube to vary with variations in humidity.

FREDRICK S. MARCEILUS. 

